Portable combustion-powered tools, having various different means for conducting or charging a combustible fuel into a suitable combustion chamber, are of course well-known. Examples of such portable power tools are disclosed within U.S. Pat. No. 6,912,988 which issued to Adams on Jul. 5, 2005, U.S. Pat. No. 4,905,634 which issued to Veldman on Mar. 6, 1990 and U.S. Pat. No. 4,821,683 which issued to Veldman on Apr. 18, 1989. In accordance with the disclosures of such patents, the portable combustion-powered tools can utilize any one of various gaseous fuels, such as, for example, compressed natural gas, liquid petroleum gas, butane, or the like. In addition, the introduction of the incoming gaseous fuel is also utilized to effectively induce or entrain the flow of ambient air into the combustion chamber of the power tool either for scavenging purposes in connection with residual gases that will be present within the combustion chamber upon completion of a particular power tool firing cycle, or for charging purposes in connection with the preparation for and initiation of a subsequent power tool firing cycle. While the portable combustion-powered tools, as disclosed within the aforenoted patents, are generally satisfactory, it is noted that such portable power tools nevertheless exhibit some operational drawbacks or limitations, particularly when it is desired to utilize liquid fuels as the fuel source. For example, while it is often desirable to operate such portable combustion-powered tools with liquid fuels as the fuel sources it is important that the liquid fuels firstly be converted into gaseous fuels so as to enable the fuels to undergo properly controlled combustion. In connection with the conversion of the liquid fuels into gaseous fuels, it is also important that a predetermined amount of the liquid fuel be supplied so as to achieve proper or more accurate stoichiometric air-fuel ratios.
A need therefore exists in the art for a new and improved liquid fuel supply and evaporator system for use in connection with portable combustion-powered tools, such as, for example, portable combustion-powered fastener-driving tools, wherein the fuel supply and combustion chamber system can utilize liquid fuels, wherein the liquid fuel can be rapidly and efficiently converted into a gaseous fuel by means of a new and improved fuel evaporator system, and wherein the liquid fuel supply and evaporator system can utilize a portioning valve structure for providing a predetermined amount of the liquid fuel to be discharged into the fuel evaporator system for conversion into a gaseous fuel for use within the combustion chamber of the portable combustion-powered fastener-driving tool.